Some games are daft.
Some games take your favourite childhood heroes, strip away all of their serious human parts, and throw them at warped versions of their nemeses. Blast Snapezilla with your Wibbly-wand-wielding one-armed Wizard until you reach level 10, or die trying!
Some games encourage you to backstab all of your friends, make silly jokes, puns, run like a coward, and sometimes even cheat.
That's your basic Munchkin. It's all gravy if you can get away with it!